PKCS#12
also: PKCS12, .p12, .pfx, PFX
PKCS#12 is a standard binary format for storing private keys, certificates, and certificate chains in a single encrypted file, commonly used for securing private keys and their associated credentials.
PKCS#12 (Public Key Cryptography Standard #12) is a standardized file format defined by RSA Laboratories for bundling cryptographic credentials. It typically contains a private key, its corresponding X.509 certificate, and optionally the certificate chain—all protected with password-based encryption.
The format is commonly seen with file extensions .p12 or .pfx (PKCS#12 for Exchange). It's widely used for storing credentials in web servers, email clients, and certificate distribution. For example, a web administrator might export an SSL/TLS certificate and private key from a certificate authority into a single .p12 file to import into an Nginx or Apache configuration.
You can work with PKCS#12 files on Linux using openssl. To extract a certificate from a .p12 file: openssl pkcs12 -in cert.p12 -clcerts -nokeys -out cert.pem. The main advantage is portability—a single encrypted file containing all credentials needed for secure communication.